Leigh syndrome

Leigh syndrome is a rare, progressive neurological disorder caused by impaired cellular energy production, usually from genetic defects affecting mitochondria. It most often begins in infancy or early childhood and damages specific regions of the brain.

Oxidative phosphorylation: The mitochondrial process that uses oxygen to produce most cellular ATP through the electron transport chain and ATP synthase. Defects in this energy-producing process cause many cases of Leigh syndrome.
Mitochondrion: A cell structure that generates much of the cell’s ATP and performs other metabolic functions. Most known causes disrupt proteins that function in or support these organelles.
Magnetic resonance imaging: A medical imaging method that uses magnetic fields and radio waves to create detailed images of the body. MRI can reveal characteristic bilateral lesions in deep gray matter or brainstem.
Leigh-like syndrome: A neurological condition resembling Leigh syndrome clinically or radiologically but not meeting its defining criteria or having another established cause. The label distinguishes overlapping presentations from the classic syndrome.
Mitochondrial respiratory chain: A series of protein complexes in the inner mitochondrial membrane that transfers electrons and helps generate ATP. Disruption of its complexes is a frequent biochemical cause of the disorder.
Mitochondrial DNA: The small circular genome found in mitochondria, encoding some proteins and RNAs needed for mitochondrial function. Variants in this genome can cause Leigh syndrome and follow maternal inheritance.
Genetic testing: Laboratory analysis of DNA to identify variants associated with inherited traits or disorders. Testing can identify the causal gene and clarify inheritance for affected families.
MELAS: A mitochondrial disorder characterized by mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes. MELAS shares mitochondrial dysfunction and lactic acidosis but has a distinct clinical pattern.
Pyruvate dehydrogenase complex: A group of enzymes that converts pyruvate into acetyl-CoA, linking glycolysis to the citric acid cycle. Defects can impair energy metabolism and produce a Leigh syndrome presentation.
Nuclear DNA: The DNA housed in a cell nucleus, containing most of an organism’s genetic information. Most Leigh syndrome genes are nuclear, so inheritance often follows Mendelian patterns.

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Mitochondrial replacement therapyBroader topic: Some families at risk of severe mitochondrial disease consider reproductive options such as replacement.